Swivel caster



ANov. 22, 1927. 1,649,946

C. W. BROSTEDT SWIVEL CASTER Filed Nov. lO. 1926 IN VEN TOR Mag/W BYKML7M A TTORNEYU 'Patented Nov. 22, 1927..

"UNITED STATES PATENT OFFICE.

CARL BROS'JIED'I, 0F SPRINGFIELD, 'MASSAGHUSETTS, ASS-IGNOR T0 THE GEORGE P. Cnam; COMPANY, OF NECTICUT.

Application led November 1,0, 1926. Serial No. 147,573.

This invention relates to improvements in trailers, trucks, or the like, and is directed freely turn onits axis so. that the castery wheels will track with the supporting wheels as the truckrounds curves, etc.

These casters of the prior art are intended to support their portion of the load and, being arranged for a swivelling action, they are non-yieldable to such forces as are frequently applied thereto in directions opposed to their pivotal axis. For instance, when the caster wheels strike against an obstruction, the force is transmitted directly against the swivel or pivot which tendsto' break or bend `7the pivot so as to impair its pivotal action or otherwise injure or damage the caster.

The principal object of this invention is to provide a swivelled caster which is construct- A ed and arranged to be resiliently connected to the truck for resiliently supporting the same and so as to be yieldable when acted upon by forces applied thereto in directions opposed to the pivotal axis thereof. Its yieldable characteristics provide a cushioninv means for absorbing Shocks and jolts caused by forces applied thereagainstl so that its swivelling features are not injured or impaired thereby. The cushioning is accomplished by means of the novel structure com prising the invention which will now be dis-y closed in the format present preferred with reference to the accompanying drawings, in Which:-

Fig. l is a side elevational view ofa truck or trailer having associated therewith a resiliently mounted caster forming a part of the invention;

Fig. 2 is a plan viewA of the truck shown in Fig. 1; and

Fig. 3 is a side elevational view of the forward end of the truck and caster showing the parts in a different relative position from that shown in Fig. 1.

Referring to the ydrawings in detail,a trailer or truck frame 1 is shown that comprises longitudinal side sills 2 and transverse end sills 3 which are suitably secured together by Corner gusset plates 4 as shown. A box like body, platform, or any other form of body (not shown) maybe secured to and carriedf by the frame as is usual. One end of the frame is shown as being resiliently supported by springs '5 from an saxle 6 which is in turn carried by Wheels 7 at either end thereof.

To tie the1 side sills 2 together, any number or style of cross ties such as struts 8 and 9 may be provided and which are preferably secured to the under side of the side sills 2 by means `bf bolts b or the like,/and while arranged to function as vstiifeners for the frame, they are also arranged to cooperate with and support the parts forming the novel features ofthe invention as will now be described.

A transverse spring 12, preferably of the half elliptic leaf type is securedintermediate f its ends to the cross bar 8 by U bolts 13 in the usual manner and is provided at opposite ends with the usual eyes or loops 14 of ordinary form. The cross bar 9 is provided with cylindrical trunnions 9 at the ends thereof which extend beyond the side sills 2, and links 10 oseillatable on said trunnion, are preferably formed to have separated or spaced apart arms 10' which embrace or straddle pivot bearing members 11. These members 11 are pivotedto the ends of said arms by means of pins 12 as shown. Arms` 13 extending from and' integral with the members 11 are suitably connected at their ends by links 15 and 15 to the eyes or loops 14 of the spring 12. Stops 16 integral with the members 11 are arrahged to abut'the under side of the links 10 as shown .in Fig. 2

for the purpose later to be described.

Swivel members 17, in the form of forks having castern wheels 18 pivoted thereto, have upstanding pivotal spindles or Shanks 19 which are rotatable on a vertical axis in the members 11 and are held from displacement therefrom by any suitable means such order that the wheels 18 may trail or accommodate themselves to the direction of movement'of the truck. f

Withthe parts in the relative positions shown in Fig. 1, the frame will, when loadloadl and trailing ed, be lowered to some extent depending of course, upon the weight o f the load and the characteristics of the springs. The rear springs under a load will yield in the usual manner, while the forward transverse spring will be acted upon inkthe manner now to be described.

As the cross bar 9 with its trunnions 9 is lowered with the frame, the links 10 will be swung downwardly thereby but since the links 10 are iny abutment with the stops 16 of the members 11 as shown in Fig. 1 the swinging action of the links will also tend to swing the members 11 so that the wheelsl 18-thereof will move relative to the frame and along the ground or floor in a rearward direction. rll.`he arms 13 of the members will be raised by this swingingmovement and, being pivotally connected to the ends^of the spring 12, their ability to raise and consequently the freedom with which the frame may lower lis dependentupon the resistance of the spring and the relative weightA of the load. Thus, the frame at its caster end is resiliently supported by means of the spring 8. As the truck is being moved along an uneven Hoor or the like, the caster structure in supporting its portion of the or tracking the other wheels as is its notion, is brought into contact with obstructions as indicated in Fig. 3. As the wheel 18 of the ifork brings up against an obstruction, a forcejs applied to the wheel and fork which tends to swing the same together with the member 11 rearwardly against the action of the spring 8. The spring is preferably adapted to cushion the force ofthe blow which blow except for the.. spring structurewould be delivered directly to the pivot of the fork in directions opposed to itsipivotal axis. In effect, the caster iswenabled yto yieldingly resist these opposin forces so that the pivot thereof is protecte against injury. The fork 18 and member 11 will be swung more or less according to the nature of the obstruction in the path of the wheel and' the characteristics of the spring, which spring mayl be varied to suit various conditions. The connections between the parts may, of course, be varied within wide limits depending upon the type of truck with which the device is used but will preferably be arranged to absorb the blow. and to urge the caster wheel towards the ground at all times so that the load is supported resilient-slythereby and the mounted casters for one end' of the truck it willl be obvious that the invention .may be adapted where it is desired tov employ but a single caster or any other desired number `for supporting the frame at either or both its ends. i

From the foregoing it will be observed that l haveprovided a novel structure including a swivel caster for a truck or the like and interconnecting means, which are adapted and arranged whereby the frame is resiliently supported by a caster and whereby the ycaster is resiliently yieldable against forces applied thereto in directions opposed to' its pivotal axis. c

l am aware that many changes may be made in the form of the invention without departing from the novel features thereof and l prefer therefore, to be limited by the appended claims rather than by the foregoing description of the preferred form of the invention. f

at lf claim is:

1. The combination with a truck, orpthe like of a resilient swivel support therefor comprising, a 'swivel bearing mounted on said truck for a swinging movement m'a certain plane, a swivel caster pivoted 1n said bearing for movements in a plane transverselv to said certain plane, a. spring interposed between said bearing and said truck for resiliently supporting the bearing an caster against forces applied thereto 1n d1- rections opposed to said pivotal axis. 2. The combination with a truck4 or the like of a. `resilient swivel support therefor comprising, a link pivotally mounted on said truck, a swivel caster pivotally carried by said link, and a vspring separated from said link interposed between said caster and said truck for resiliently supporting the'caster aganst forces applied thereto in directions opposed to the pivotal axis thereof.

3. The combination with a truck or the like of a .resilient swivel support` therefor comprising, a link pivoted on said truck, a swivel caster pivoted thereto, means for limiting a relative movement of said link and caster in one direction, a spring interposed between said caster and truck all adapted and Varranged whereby a lowering movement of the truck will move the caster against the action of the spring. while an upward movement 'will permit the spring to urge the caster downwardly.

4. The combination with a truck or the like of a resilient swivelfsupport therefor llO comprising,^swivel casters mounted on pivto that lof their swivel ingsaid'casters against forces aplplied thereto in directions opposed to t eir pivotal XeS. 1

5. The combination with a truck or thav like of a resilient swivel supportl therefor comprising, a vlink pivoted for movement on said truck lin a vertical direction, a swivel Abearing pivoted to said link on an axis parallel to the pivot of said link, a fork in said bearing pivoted on an axis transversely to said arallel'pivotal axes, 'an arm integral with aid bearing extending therefrom transversely to the pivotal axis of said fork, and' a link connected to said arm and frame for supporting said swivel fork and bearing against movements in directions opposed to the ivotal axis of said fork.

6. Thecom ination with a. truck or the like. of a resilient swivel supporttherefor comprising, a link having its forward end pivoted to said frame on a horizontal axis] with said bearing and extending to the rear thereof and a springinterposed between the said arm and frameto support said hearing and fork against movement in directions op` posed to the pivotal axis thereof.

In testimony whereof signature.

to limit the relatlve movement thereof, a ever arm integral I have aixed my 

